Window Vista SP1 will released through Microsoft update but due to window sp1 patch are large (more than 700 MB),once download through Microsoft window server 2003,the download operation does not succeed.

This problem occurs because WinVerifyTrust function in window server 2003 has a bug inside.Microsoft advised the window vista users install the WinVerifyTrust patch,this patch is a hotfix (not a public GDR),so is not intended to be widely distributed.